Theoretical Study on a Supramolecular Dimeric Structure Constructed by Metallofullerene Y 3 N@C 80 and Figure-of-Eight Nanoring.

A new supramolecular complex with a dimeric structure (2YN@C⊂OPP) constructed by metallofullerene YN@-C and figure-of-eight molecular nanoring of oligoparaphenylene (OPP) was investigated using dispersion-corrected density functional theory (DFT-D3). The interactions between the YN@-C guest and the OPP host were studied theoretically at the B3LYP-D3/6-31G(d)∼SDD level. By analyzing geometric characteristics and host-guest binding energies, it is revealed that the OPP is an ideal host molecule for the YN@-C guest. Typically, the OPP can well induce the orientation of the endohedral YN cluster on the plane of nanoring. Meanwhile, the configuration of the dimeric structure demonstrates that OPP presents excellent elastic adaptability and shape flexibility during the encapsulation of YN@-C. Highly accurate binding energy suggests that 2YN@C⊂OPP (∼-443.82 kJ mol at the ωB97M-V/def2-QZVPP level of theory) is an extremely stable host-guest complex. Thermodynamic information indicates that the formation of the 2YN@C⊂OPP dimer is thermodynamically spontaneous. Furthermore, electronic property analysis reveals that this dimeric structure has a strong electron-attracting ability. Energy decomposition and real-space function analyses of host-guest interactions reveal the characteristics and nature of the noncovalent interactions in the supramolecules. These results provide theoretical support for the design of new host-guest systems based on metallofullerene and nanoring.